Governing Realtime API WebSocket and voice traffic through a proxy
Govern realtime traffic by treating the session, not the request, as the unit of control. Bind identity at the handshake, enforce policy on streamed frames and mid-session events, gate tool calls before they execute, and write audit records at every lifecycle stage. Keep inline checks light enough that voice interaction does not degrade.
How realtime sessions differ from HTTP API traffic
Realtime and voice traffic is carried over a session rather than a single request, so governance has to follow the session from start to finish. Controls are applied at four points: the handshake, the streaming phase, tool calls, and termination.
Controls across a proxied realtime session
| Stage | Control |
|---|---|
| Handshake | Authenticate the upgrade request and bind the session to an agent identity. |
| Streaming | Apply policy to frames and mid-session events within a latency budget. |
| Tool calls | Evaluate each requested action against the agent's permissions. |
| Termination | Close cleanly, enforce limits, and flush the audit record. |
A reference architecture for a realtime proxy
A governing proxy sits between the client or agent and the model provider endpoint. The components below are logical and can be combined in a single deployment.
- Session terminator. Ends the client WebSocket and opens a separate upstream connection, giving two legs that can be controlled independently.
- Identity and authorization. Resolves the handshake credential to an agent identity and decides which models, tools, and data modes the session may use.
- Frame and event inspector. Evaluates policy against frames and control events, using per-session state.
- Tool-call gate. Checks requested tool or function calls against the agent's permissions before they proceed.
- Session controller. Enforces duration, rate, and concurrency limits and can terminate a session on policy violation.
- Audit pipeline. Receives session events asynchronously so logging stays off the latency-critical path.
Latency, logging, and data handling tradeoffs
Inline checks should stay light enough that voice interaction does not degrade. The audit pipeline supports this by receiving session events asynchronously, which keeps logging off the latency-critical path.
When assessing a proxy, ask for the measured latency overhead of per-frame and per-event policy. Also ask how audio and transcript data are inspected, redacted, stored, and retained, and whether retention is configurable.
What the proxy can enforce and what belongs elsewhere
At the proxy, identity is bound at the handshake, policy is applied to frames and events, tool calls are gated against permissions, and duration, rate, and concurrency limits are enforced. The session controller can terminate a session on policy violation, and an audit record is written at each lifecycle stage.
Evaluation criteria for a realtime proxy or gateway
- Which realtime transports does it support, and how does it handle upgrade and reconnection?
- How is a session bound to an agent identity at handshake, and does that identity appear in every audit record?
- Can policy apply to individual frames and mid-session events, and what is the measured latency overhead?
- How are audio and transcript data inspected, redacted, stored, and retained, and is retention configurable?
- Can tool calls be gated by least-privilege permissions, with approval for sensitive actions?
- Does the vendor state clearly which controls the proxy enforces and which remain with the application or provider?
Plan governance for your realtime traffic
Talk through session identity, tool-call controls, and audit requirements for realtime and voice agents with a Trussed AI expert.
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